That's awesome. I'll have to use that tool to correctly set my cards tomorrow. One thing I noticed with Geforce mining is the CPU usage is much higher than with Radeon cards and while running other tasks I notice some slowdown and hitching which is not an issue on the Radeon systems. Perhaps it's just a Windows 10 thing with Geforce, not sure...I'm using 8192 and 256 atm.
Download the below tool. Go to the OpenCL tab. It will tell you the maximum values your card supports. 2D image size is the global work size. Work group size is the local work size.
You can think of the works values like intensity from Bitcoin. My computer shows no adverse effects with any combination of work values.